Adjustable brake-shoe stop



Sept. 2, A1930. M. LouGHEAD ADJUSTABLE BRAKE SHOE STOP vFiled Aug. 18,1928 i Patented -Sept. 2, 1930 UNITED STATESv PATENT OFFICE` MALCOLMLOUGIIEAD, voir DETROIT, MICHIGAN, AssIeNoR To HYDRAULIC -BRARE COMPANY,OF DETROIT, MICHIGAN, A CORPORATION oF CALIFORNIA ADJUSTABLE BRAKE-SHOESTOP Applicationled August 18, 1928. Seria1 No. 300,420.

This invention relates to a braking apparatus and is herein shown anddescribed as applied to automobiles and particularly to brakingapparatus of the fluid pressure operated type.

The principal feature of the invention resides in means for limiting theretractile movement of brake shoes to compensate for wear ofthe brakesurfaces so that the brake operating mechanism retracts throughsubstantially the same distance as when the braking surfaces are intheir initial condition; that is, means are' providedfor adjusting abrake shoe stop so that the brake shoe is re tracted the same amountafter it has become worn as when it is new.

An obj ect of this invention is to provide an adjustable stop for thebrake shoes which may be 'adjusted withoot disassembling the brakemechanism.-

A further object of the inventionis to provide an adjustable vstopmechanism which may be adjusted by means of a set screw oonvenientlylocated in an accessible portion of the-brake housing.

It is believed that a complete understanding of the invention may be hadby reference to the following description taken in conjunction with theaccompanying drawing, in which Fig. 1 is a front elevation, partly insection, of a brake assembly embodying the invention;

Fig. 2 is across-sectional view of the apparatus taken on lines 2-2 ofFig. 1; and

Fig. 3 is a fragmentary sectional view taken on lines 3 3 of Fig. 2.

Referring to the drawing, the invention is illustrated in connectionwith a hydraulic brake of the internal type in which a drum 4,-which isattached to the vehicle wheel or other rotatable member, not shown,surrounds the operating parts of the brake mechanism, which are mountedupon apan 5. A pair of brake shoes 9, each comprising an arcuatesection6, which is provided with a brake linin 7 and an inwardly projectingIflange 8 is plvotally mounted upon'an anchor pin 11 attached to thelower portion of the pan 5. A plurality of shouldered guide and- 4theflange 8 of the brake shoe.

spacer pins 12 carried by the pan project through slots in the flangesSto guide the movement of the brake shoes and `hold them in properlyspaced relation with the pan to prevent the heavy rims ofthe shoes fromrat- 1tion by a spring 15.

A stop mechanism is provided to limit the ret-Tactile movement of thebrakeshoes so that as the lining becomes worn and a greater `movement ofthe brake shoes toward/the drum is'required, the vretractile movementcan be-correspondingly decreased so as to maintain a constantyclearancebetween the brake shoes and the drum when the brake shoes arein their inoperative position, resulting in a uniform stroke of thepistonsof the fiuid motor. 1

The stop mechanism comprises a U-shaped member 16 which is attached tothe pan 5 and has a slot 17 in each arm for receiving Pivotally mountedwithinv the U-shaped member l16 upon a pin 18 is a bell crank lever 20forming a stop member, one arm of which 4extends to the base of theslots 17 and into the path of the fiange 8 and the other arm vof whichrestsV upon a set screw 19 which is threaded through the pan 5. A locknut 21 is associated with the set screw 19 to securely lock it againstrotation when the stop member 20 has been adjusted. As the brake liningbecomes worn and the shoe 9 approaches nearer the -drum 4, the set screw19 the head of which extends outside of the` housing formed by the pan 5and the drum 4, may be rotated to pivot the stop member 20jabout the pin18, causing the arm ofthe stop member `20` to follow the flange 8 oftheshoe 9 and thus decrease the lretractile movement of the shoe.

The invention thus provides a simple and convenient means for adjustingthe amount of movement .of the brake shoes of a brake stling against thepan. The brake shoes are mechanism of the internal brake type With- -outthenecessity of removing the vehicle. wheel or disassembling the brakemechanism ingan inwardly projecting flange, a support for the brakeshoe, a U-shaped member mounted on the support and having a slot forreceiving the flange of the brake shoe, and an adjustable stopl membermounted in the U-shaped membergfor limiting the movey ment of the flangein the slot.

2. In a brake mechanism, a brake shoe havin an inwardly projectingflange, a support orthe brake shoe, a U-shaped member mounted on the4support and having a slot for receiving the flange of the brake she, astop member pivotally mounted in the U- shaped member for limiting themovement of the flange in the slot, and a set screw threaded into thesupport operable to position the stop member to determine the stopposition of the brake shoe.v j

3. In a brake mechanism, a brake' drum, a relatively stationary supportforming a housing with the drum, a brake shoe pivoted for movement onsaid support-and adapted to moveparallel thereto, a member mounted onsaid support and adapted to guide said brake shoe in movementfabout itspivot, a stop movablyvcarried by saidmember, and adjustable meanscontacting with said stop and extending through said su port tov permitadjust- Lment of said stop rom outside the brake housing.

4. In a brake mechanism, a brake drum, a relatively stationary supportforming a housing with the drum, a brake element movably carried by thesupport and adapted to move into contact with said drum, a U-shapedmember mounted on the supporta bell crank lever pivotally mounted in`said .U-shaped member and protected thereby, one arm of said bell cranklever abutting a portion of the brake shoe and constituting a stoptherefor, and adjustable means abuttlng the other arm of said bell cranklever Vand extending through said support to permit adjustment of thestop position of-the brake shoe from outside of the brake housing.

5. In a vehicle brake, a brake drum, a relatively stationary supportforming a 'brake shoe housing with the drum, a brake shoe pivotallymounted on said support for movement into and out of contact with saiddrum, a bell crank lever carried by the support and pivoted for movementon an axis perpendicular to the brake vshoe pivot, one arm of the bellcrank lever abutting a portion of the brake shoe and constituting a stoptherefor,

and a threaded member extending through the housing in a directionperpendicular to both of said pivots and abutti'ngthe other army of thebell crank lever, said threaded member adjustable from outside the brakehousing whereby the stop position of th brake shoe is readly adjustable.

I n witness whereof, I hereunto subscribe my name this '14th day ofAugust, 1928.

MALCOLM LOUGI-IEAD.

